JP2002275396A - Ink for ink jet recording and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink for ink jet recording (aqueous dispersion) excellent in dispersion properties and storage stability, a method of manufacturing the same, also an ink for ink jet recording (aqueous dispersion) which gives both sharpness and light fastness to resultant images, and a method of manufacturing the same. SOLUTION: There is provided an ink for ink jet recording which comprises at least a dispersant, water, a water-base organic solvent, and fine dispersible solid particles of an organic dye having a chelate structure, wherein the dispersant is an nonionic dispersant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording ink and a method for producing the same, and more particularly, to an aqueous ink-jet recording ink excellent in dispersibility, storage stability, image sharpness and light fastness, and a method for producing the same. .

[0002]

2. Description of the Related Art Inks used in an ink jet recording system include inks containing various coloring materials. Among such inks, inks in which a coloring material is dispersed in a liquid medium, such as an aqueous dispersion ink of an oil-soluble dye and an aqueous dispersion ink of a disperse dye, have low dispersibility of the coloring material and are caused by this. And storage stability (the term “storage stability” as used herein refers to the absence of aggregation and sedimentation of the color material and the increase in the viscosity of the ink) and the storage stability under severe storage environments (as used herein). The storage stability is a high temperature environment of 60 ° C or a storage environment of 10 ° C-60 ° C cycle,
(Which means that the aggregation and sedimentation of the coloring material and the increase in the viscosity of the ink do not occur).

[0003] For the purpose of solving the above problems, for example, Japanese Patent Application Laid-Open No. 8-333331 discloses the use of a condensation product of 2-naphthalenesulfonic acid and formaldehyde as a dispersant. Kaihei 8
Japanese Patent No. 291266 proposes to use an aromatic polyvalent anion dispersant as a dispersant. However, Japanese Patent Application Laid-Open Nos. 8-333331 and 8-29
Even with the use of the ink jet recording ink described in Japanese Patent No. 1266, improvement in storage stability was still insufficient depending on the type of coloring material.

[0004] In general, dye inks are excellent in terms of image quality such as sharpness as compared with pigment inks, but tend to have poor light fastness. In order to obtain inks having excellent light fastness, pigment inks are used. I had to choose. However, there is a problem that the pigment ink is inferior in image quality such as sharpness as compared with the dye ink.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet recording (water-based dispersion) ink having excellent dispersibility and storage stability, and a method for producing the same. It is in.

Another object of the present invention is to provide an ink for ink-jet recording (water-based dispersion) having both sharpness and light fastness of an obtained image, and a method for producing the same.

[0007]

The above object of the present invention is achieved by the following constitution.

[0008] 1. An ink jet recording ink containing at least a dispersant, water, an aqueous organic solvent, and a solid fine particle dispersion of an organic dye having a chelate structure, wherein the dispersant is a nonionic dispersant.

[0009] 2. The ratio of the mass (B) of the nonionic dispersant to the mass (S) of the organic dye having a chelate structure ((B
/ S) × 100%) is 5 to 100%.

[0010] 3. 3. The ink jet recording ink according to 1 or 2, wherein the metal atom forming the chelate structure with the organic dye is nickel, copper, chromium, cobalt, zinc or iron.

4. In a method for producing an inkjet recording ink containing at least a solid fine particle dispersion of an organic dye obtained by subjecting a mixture of at least a dispersant, water, an aqueous organic solvent and an organic dye having a chelate structure to a nonionic dispersion, A method for producing an inkjet recording ink, which is a dispersant.

5. The ratio of the mass (B) of the nonionic dispersant to the mass (S) of the organic dye having a chelate structure ((B
(S) x 100%) is from 5 to 100%.

6. 6. The method for producing an ink for inkjet recording according to 4 or 5, wherein the metal atom forming the chelate structure with the organic dye is nickel, copper, chromium, cobalt, zinc or iron.

Hereinafter, the present invention will be described in detail. In the present invention, as an organic dye having a chelate structure (hereinafter, also simply referred to as a chelate dye), a chelate dye represented by the following general formula (1) is preferably used.

General formula (1) M (Dye) _l (A) m (where M represents a metal ion and Dye represents a dye capable of coordinating with the metal ion. A represents a dye represented by Dye) L represents an integer of 1 to 3;
Represents an integer of 0, 1, 2 or 3. When m is 0, 1 represents an integer of 2 or 3, and Dye may be the same or different. In the general formula (1), as the metal ion represented by M, a metal atom belonging to Groups I to VIII of the periodic table, for example, Al, Co, Cr, Cu, Fe, Mn, Mo, Ni, S
Examples include metal ions of metal atoms such as n, Ti, Pt, Pd, Zr and Zn. Ni, C from the point of color tone and light resistance
Metal ions of metal atoms such as u, Cr, Co, Zn, and Fe are preferable, and Ni ions are more preferable.

In the general formula (1), the dye capable of coordinating with the metal ion represented by Dye includes various dye structures, and conjugated methine dyes, azomethine dyes,
Dyes having a coordination group in the azo dye skeleton are preferred. Color tone,
Dyes represented by the following general formulas (2) to (7) are particularly preferable from the viewpoint of light fastness.

[0017]

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(In the general formulas (2) to (7), X is a group capable of forming a dye via a conjugated system and capable of forming a monodentate to tridentate chelate (coordination bond with a metal ion). Y represents a group of atoms forming a 5- or 6-membered aromatic carbocyclic or heterocyclic ring, and in the general formulas (2) to (4), R ₁ , R ₂ , R ₃ represents a hydrogen atom, a halogen atom or a monovalent substituent, and n represents 0, 1 or 2
Represents an integer. In the general formulas (2) to (7), X is a group which forms a dye via a conjugated system, and is a group or atom capable of forming a monodentate to tridentate chelate (coordination bond with a metal ion). Represents a group, for example, when the N, S, and O elements form a part of the substituent of the aromatic ring of X and have a dissociated, non-dissociated structure,
Alternatively, a case where a heterocycle of X is formed can be mentioned. The substituent (N capable of coordinating with a metal ion,
Examples of the substituent containing the S and O elements) include, for example, 1
Primary, secondary, and tertiary amino groups (for example, amino group, methylamino group, dimethylamino group, diethylamino group, etc.), mercapto group, thioether group, hydroxy group, carboxy group, carbonyl group, sulfo group, and the like. it can. Examples of the hetero ring include a pyridine ring, a pyrimidine ring, a furan ring, a thiophene ring, a thiazole ring, an imidazole ring, a 3H-pyrrole ring, an oxazole ring, and a 3H
-Pyrrolidine ring, oxazolidine ring, imidazolidine ring, thiazolidine ring, 3H-indole ring, benzoxazole ring, benzimidazole ring, benzothiazole ring, quinoline ring, isoquinoline ring, indolenine ring, barbitur ring, thiobarbitur ring, Examples include a rhodanine ring, a hydantoin ring, a pyrazolidinedione ring, a pyridinedione ring, a pyrazolone ring, and a pyrazolotriazole ring.

In the general formulas (2) to (7), Y represents a group of atoms forming a 5- or 6-membered aromatic carbocyclic or heterocyclic ring, and further has a substituent on the ring. And may have a condensed ring. Specific examples of the ring include a benzene ring, a naphthalene ring, a pyridine ring, a pyrimidine ring, a furan ring, a thiophene ring, a thiazole ring, an imidazole ring, a naphthalene ring, a 3H-pyrrole ring, an oxazole ring, a 3H-pyrrolidine ring, and an oxazolidine ring. , An imidazolidine ring, a thiazolidine ring, a 3H-indole ring, a benzoxazole ring, a benzimidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, an indolenine ring, a barbitur ring, a thiobarbitur ring, a rhodanine ring, a hydantoin ring, Pyrazolidinedione ring,
And a pyridinedione ring. These rings may further form a condensed ring with another carbon ring (for example, a benzene ring or the like) or a heterocyclic ring (for example, a pyridine ring or the like). Examples of the substituent on the ring include an alkyl group, an aryl group, an acyl group, an amino group, a nitro group, a cyano group, an acylamino group, an alkoxy group, a hydroxy group, an alkoxycarbonyl group, and a halogen atom. It may be substituted. Y may have a coordinable group.

In the general formulas (2) to (4), R ₁ ,
R ₂ and R ₃ represent a hydrogen atom, a halogen atom or a monovalent substituent, and n represents 0, 1 or 2, and the monovalent substituent is an alkyl group (for example, a methyl group, an ethyl group). etc),
Alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, isopropoxycarbonyl group, etc.), carboxy group, alkylamino group (eg, methylamino group, ethylamino group, propylamino group, etc.), dialkylamino group (eg, Methylamino group,
Ethylamino group), phenyl group and the like. Among them, a hydrogen atom, a halogen atom, and an alkyl group are preferable,
Hydrogen atoms are more preferred.

In the general formula (1), A represents a ligand other than the dye represented by Dye, and the ligand other than the dye represented by Dye includes an anion and a neutral molecule. There are cases. Examples of when A is a neutral ligand include, for example, halide ion, hydroxo ion, nitrate ion, cyano ion, thiocyanate ion, peroxo ion, azide ion, carbonate ion, sulfate ion, tetrafluoroboron ion and the like. Inorganic anions. Acetic acid, oxalic acid, maleic acid, succinic acid, acetylacetone, salicylaldehyde, glycine, ethylenediamine diacetic acid,
Examples include anions such as ethylenediaminetetraacetic acid, benzoic acid, p-toluenesulfonic acid, phenol, phthalic acid, picolinic acid, thiophenol, and dithiolbenzene, and anions of derivatives of these molecules. Examples when A is a neutral ligand include, for example, ammonia, water, triphenylphosphine, 1,3-propanediamine,
2'-bipyridine, 1,10-phenanthroline, glycinamide, diethylenetriamine, 2,2 ', 2 "-
Terpyridyl, triethylenetetramine, ethylenediamine and the like can be mentioned.

Specific examples of the dye capable of coordinating with the metal ion represented by Dye of the general formula (1) are shown below.
The present invention is not limited to these.

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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Specific examples of the ligand other than the dye represented by Dye represented by A in the general formula (1) are shown below, but the present invention is not limited thereto.

[0031]

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[0032]

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[0033]

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Examples of the compound of the chelate dye of the present invention are shown below. General formula (1) M (Dye) _l (A) _m M: metal ion, Dye: an example compound number of a dye capable of coordinating with a metal ion, l: the number of Dye, A: a ligand other than the dye Illustrative compound number, m: Indicates the number of A.

[0035]

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The above-mentioned dyes are preferable examples that can be used in the present invention, and the present invention is not limited to the above-described dyes. These, alone,
Alternatively, two or more kinds may be used in combination. These may be newly synthesized. In the present invention, when a dye is dispersed in a dispersion liquid containing a dye (pigment), water, a dispersant, an organic solvent and the like into a solid fine particle dispersion, the dye is taken out in a wet cake state during the production of the dye. It is preferable to use a dye which has good dispersion of fine particles. That is, when such a wet cake dye is subjected to dispersion treatment, solid fine particles can be efficiently dispersed. However, the use of a dye taken out in the form of a wet cake is basically a problem of work efficiency and does not greatly affect the attainable performance, and is not an essential condition in the present invention.

Examples of the dispersing machine used for dispersing the dye into a solid fine particle dispersion include a sand mill, a ball mill, a roll mill, an agitator, an attritor, a high-pressure homogenizer, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, and the like. Various types such as a wet jet mill and a paint shaker can be used alone or in appropriate combination, but the present invention is not limited to these.

The beads used for dispersion treatment in a dispersing machine are preferably ceramic beads having a particle size of 1.5 mm or less, more preferably zirconia beads having a particle size of 0.5 mm or less. The filling rate of the beads used in the disperser may be arbitrary. The peripheral speed of the disk of the dispersing machine is preferably 10 m / sec or more, and the dispersion time is preferably 60 minutes or more as the residence time of the dispersion containing the pigment, water, dispersant and organic solvent.

In the present invention, the dispersant means one having a function as a wetting agent, a surfactant, and a stabilizing (or preventing aggregation) agent.

Examples of the nonionic dispersant of the present invention include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester,
Dispersants selected from the group consisting of glycerin fatty acid esters, polyoxyethylene fatty acid esters and alkyl (poly) glycosides can be used. Nonionic dispersants preferably used are selected from polyoxyethylene alkyl ethers and polyoxyethylene alkyl aryl ethers. These may be used alone or in combination of two or more.

In the present invention, the ratio of the mass (B) of the nonionic dispersant to the mass (S) of the organic dye having a chelate structure ((B / S) × 100%) is preferably 5 to 100%. 5-80% is more preferred. 5%
If it is less than 10, the wettability of the dye with water is significantly reduced, and the dispersibility may be deteriorated. On the other hand, if it exceeds 100%, the finely divided solid dye becomes easy to dissolve, and the dissolved dye precipitates due to a change in temperature, concentration, etc., and promotes the growth and aggregation of the dye dispersion, resulting in remarkable storage stability. May drop.

In the present invention, the aqueous organic solvent includes
There is no particular limitation on the type of the agent as long as it has a function as a wetting agent or humectant. For example, glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol; glycerin; diethylene glycol diethyl ether , Diethylene glycol monobutyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diethyl carbitol,
Ethers of polyhydric alcohols such as triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and propylene glycol monomethyl ether; acetates; thiodiglycol; N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone , Nitrogen-containing compounds such as formamide, dimethylformamide and the like; one or more kinds such as dimethylsulfoxide can be used.

Further, the ink jet recording ink of the present invention includes a defoaming agent such as a silicone compound, a fungicide such as a chloromethylphenol compound, a benzotriazole type, a benzophenone type, a hydroxybenzoate type, a salsylate type and a cyano type. An acrylate-based ultraviolet absorber or the like may be contained.

The ink jet head used in the ink jet image recording method according to the ink for ink jet recording of the present invention may be of an on-demand type or a continuous type. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shared mode type, a shared wall type, etc.), and an electro-thermal conversion method (for example, thermal Specific examples include an inkjet type, a bubble jet (registered trademark) type, etc., an electrostatic suction type (eg, an electric field control type, a slit jet type, etc.), and a discharge type (eg, a spark jet type, etc.). However, any discharge method may be used.

[0045]

EXAMPLES The present invention will be specifically described below with reference to examples, but embodiments of the present invention are not limited thereto.

Preparation of Dispersion Liquid: 25 parts by mass of the chelating dye shown in Table 1, 20 parts by mass of ethylene glycol, and the dispersing agent shown in Table 1 in the ratio of the dispersing agent mass (B) to the chelating dye mass (S) ((B / S) ×
100%), and finally add ion-exchanged water and add
Parts by mass were used. This mixture was placed in a homogenizer (Excel Auto: manufactured by Nippon Seiki Seisakusho),
After adding zirconia beads with a diameter of 50 mm at a filling rate (volume) of 50% and dispersing for 10 hours to obtain a solid fine particle dispersion of the chelate dye, coarse particles were removed by a centrifuge (1130: manufactured by Kubota Shoji Co., Ltd.) and dispersed. A liquid was prepared.

[0047]

[Table 1]

The dispersants listed in Table 1 are shown in Table 2
Will be described.

[0049]

[Table 2]

Preparation of Ink 20 parts by weight of each of the dispersions obtained as described above and 16 parts by weight of ethylene glycol were mixed, and ion-exchanged water was added to make up to 100 parts by weight. ) And Ink-5 to 8 (comparative).

Evaluation Dispersibility: The average particle size of the prepared ink was measured five times by measuring the scattering intensity distribution of Zetasizer 1000 (manufactured by Malvern), and the measured values were arithmetically averaged to obtain the average particle size. The evaluation was performed on a 5-point scale based on the following criteria.

×: Average particle size of 600 nm or more Δ ×: Average particle size of 400 to less than 600 nm Δ: Average particle size of 200 to less than 400 nm ：: Average particle size of 150 to less than 200 nm ：: Average particle size of less than 150 nm Storage stability: The ink was stored at 60 ° C. for 3 days, and the rate of change of the average particle size was measured. The evaluation was performed on a 5-point scale based on the following criteria.

×: Change in particle size is 100% or more Δ ×: Change in particle size is 50 to less than 100% Δ: Change in particle size is less than 20 to 50% ：: Change in particle size is less than 5 to 20% ：: Particle size change rate of less than 5% Lightfastness: Photojet paper QP using MJ-800C printer (manufactured by Seiko Epson)
(Manufactured by Konica Corp.), and the image was subjected to density measurement with an optical densitometer (X-rite 938 manufactured by X-rite), and the image having a density of about 1.0 was subjected to 70,000 lux with a xenon weather meter (Atlas). Lower, 120
Irradiated for hours, the residual ratio was measured, and evaluated in four steps based on the following criteria.

：: Residual rate of 90% or more ：: Residual rate of 80 to less than 90% Δ: Residual rate of 50 to less than 80% ×: Residual rate of less than 50% Sharpness: Monochromatic printing with density of about 1.0 The image was subjected to reflection density measurement using an optical densitometer (X-rite 938, manufactured by X-rite), and evaluated in three steps based on the half-value width of the maximum absorption based on the following criteria. Here, the half value width of the maximum absorption means the wavelength width (nm) of two wavelengths which are half the absorption intensity at the maximum wavelength before and after the maximum wavelength of the reflection spectral absorption.

：: Half width is less than 100 nm Δ: Half width is less than 100 to 150 nm X: Half width is 150 nm or more The progress and results are shown in Table 3.

[0056]

[Table 3]

Table 3 shows that the present invention provides an ink jet recording ink having excellent dispersibility, storage stability, sharpness of the obtained image, and light fastness.

[0058]

According to the present invention, it is possible to provide an ink for inkjet recording (aqueous dispersion) having excellent dispersibility and storage stability, and a method for producing the same. In addition, for inkjet recording that achieves both sharpness and light resistance of the obtained image (aqueous dispersion)
An ink and a method for producing the ink can be provided.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2C056 EA04 EA13 FC01 2H086 BA01 BA02 BA53 BA56 BA59 BA62 4J039 AE07 BA31 BA32 BA36 BA37 BA38 BA39 BC07 BC09 BC10 BC11 BC12 BC13 BC14 BC15 BC20 BC29 BC32 BC33 BC36 BC40 BC44 BC50 BC51 BC52 BC53 BC55 BC59 BC65 BC68 BC73 BC77 BE02 BE12 BE22 CA06 EA35 EA44 GA24

Claims (6)

[Claims] 1. An ink jet recording ink containing at least a solid fine particle dispersion of a dispersant, water, an aqueous organic solvent and an organic dye having a chelate structure, wherein the dispersant is a nonionic dispersant. For ink. 2. The ratio of the mass (B) of the nonionic dispersant to the mass (S) of the organic dye having a chelate structure ((B
The ink for inkjet recording according to claim 1, wherein (/ S) x 100%) is 5 to 100%. 3. The ink for ink-jet recording according to claim 1, wherein the metal atom forming a chelate structure with the organic dye is nickel, copper, chromium, cobalt, zinc or iron. 4. A method for producing an ink jet recording ink containing a solid fine particle dispersion of an organic dye obtained by subjecting a mixture of at least a dispersant, water, an aqueous organic solvent and an organic dye having a chelate structure to a dispersion treatment. And a method for producing an ink for inkjet recording, wherein the dispersant is a nonionic dispersant. 5. The ratio of the mass (B) of the nonionic dispersant to the mass (S) of the organic dye having a chelate structure ((B
The method of claim 4, wherein (/ S) x 100%) is 5 to 100%. 6. The method according to claim 4, wherein the metal atom forming the chelate structure with the organic dye is nickel, copper, chromium, cobalt, zinc or iron.